files/en-us/web/css/reference/properties/margin-block-start/index.md
The margin-block-start CSS property defines the logical block start margin of an element, which maps to a physical margin depending on the element's writing mode, directionality, and text orientation.
{{InteractiveExample("CSS Demo: margin-block-start")}}
margin-block-start: 20px;
writing-mode: horizontal-tb;
margin-block-start: 20px;
writing-mode: vertical-rl;
margin-block-start: 20%;
writing-mode: horizontal-tb;
margin-block-start: auto;
writing-mode: vertical-lr;
<section id="default-example">
<div id="container">
<div class="row">One</div>
<div class="row transition-all" id="example-element">Two</div>
<div class="row">Three</div>
</div>
</section>
#container {
width: 300px;
height: 200px;
display: flex;
align-content: flex-start;
flex-direction: column;
justify-content: flex-start;
}
.row {
height: 33.33%;
display: inline-block;
border: solid #ce7777 10px;
background-color: #2b3a55;
color: white;
flex-shrink: 0;
}
#example-element {
border: solid 10px #ffbf00;
background-color: #2b3a55;
}
/* <length> values */
margin-block-start: 10px; /* An absolute length */
margin-block-start: 1em; /* relative to the text size */
margin-block-start: 5%; /* relative to the nearest block container's width */
margin-block-start: anchor-size(width);
margin-block-start: calc(anchor-size(--my-anchor block, 20px) / 3);
/* Keyword values */
margin-block-start: auto;
/* Global values */
margin-block-start: inherit;
margin-block-start: initial;
margin-block-start: revert;
margin-block-start: revert-layer;
margin-block-start: unset;
It corresponds to the {{cssxref("margin-top")}}, {{cssxref("margin-right")}}, {{cssxref("margin-bottom")}}, or {{cssxref("margin-left")}} property depending on the values defined for {{cssxref("writing-mode")}}, {{cssxref("direction")}}, and {{cssxref("text-orientation")}}.
It relates to {{cssxref("margin-block-end")}}, {{cssxref("margin-inline-start")}}, and {{cssxref("margin-inline-end")}}, which define the other margins of the element.
The margin-block-start property takes the same values as the {{cssxref("margin-top")}} property.
{{cssinfo}}
{{csssyntax}}
<div>
<p class="exampleText">Example text</p>
</div>
div {
background-color: yellow;
width: 120px;
height: 120px;
}
.exampleText {
writing-mode: vertical-lr;
margin-block-start: 20px;
background-color: #c8c800;
}
{{EmbedLiveSample("Setting_block_start_margin", 140, 140)}}
{{Specifications}}
{{Compat}}